Fertility and reproductive histories of cancer patients, especially of long-term survivors of childhood cancer and of men and women who reproduced during cancer therapy, are studied for information on the possible mutagenicity and teratogenicity of cancer treatment and to discover hereditary patterns of cancer. Current phases include intensive analysis of data from interviews and medical records of 2,285 survivors of childhood and adolescent cancer and their siblings (as 3,266 of controls) to gather information on subsequent morbidity and mortality (especially additional neoplasms), quality of life, fertility and health of offspring. Four percent of cases had subsequent cancer compared to 2% of the controls. In 7,117 offspring, 18 cancers occurred, sometimes in known patterns of single gene traits and cancer family syndromes. Half as many survivors as controls never had a pregnancy. In the subset of study subjects in Kansas, the 101 survivors had more difficulty than same-sex siblings in getting life and health insurance. In the Connecticut subset, 450 survivors encountered rejection from military service, college, and employment more often than siblings, but had the same frequency of major depressive episodes. A second phase is the completion of analysis of a voluntary registry of pregnancies in women with cancer that shows little, if any, exess of birth defects, but some excess wastage of pregnancies conceived within 12 months of completing chemotherapy. A workshop was convened in Oslo, sponsored by the Norwegian Cancer Society and the U.S. Department of Energy, to explore interest in European collaboration in collecting additional data. Plans were laid for an International Conference on Reproduction in Human Cancer.